The mixed-lineage leukemia (MLL) protein is a histone methyltransferase that is mutated in clinically and biologically distinctive subsets of acute leukemia. Rearranged mixed lineage leukemia (MLL-r) involves recurrent translocations of the 11q23 chromosome locus which lead to an aggressive form of acute leukemia with limited therapeutic options. These translocations target the MLL gene creating an oncogenic fusion protein comprising the amino-terminus of MLL fused in frame with more than 60 different fusion protein partners. Menin, a ubiquitously expressed, nuclear protein encoded by the multiple endocrine neoplasia type 1 (MEN1) tumor suppressor gene, has a high affinity binding interaction with MLL fusion proteins and is an essential co-factor of oncogenic MLL-r fusion proteins (Yokoyama et al., 2005, Cell, 123:207-18; Cierpicki & Grembecka, 2014, Future Med. Chem., 6:447-462). Disruption of this interaction leads to selective growth inhibition and apoptosis of MLL-r leukemia cells both in vitro (Grembecka et al., 2012, Nat. Chem. Biol., 8:277-284) and in vivo (Yokoyama et al., 2005, op. cit.; Borkin et al., 2015, Cancer Cell, 27:589-602).
The menin-MLL complex plays a role in castration-resistant/advanced prostate cancer, and a menin-MLL inhibitor has been shown to reduce tumor growth in vivo (Malik et al., 2015, Nat. Med., 21:344-352). Additionally, a menin-MLL inhibitor has been shown to enhance human β cell proliferation (Chamberlain et al., 2014, J. Clin. Invest., 124:4093-4101), supporting a role for inhibitors of the menin-MLL interaction in the treatment of diabetes (Yang et al., 2010, Proc Natl Acad Sci USA., 107:20358-20363). The interaction between menin and MLL or MLL fusion proteins is an attractive target for therapeutic intervention, and there is a need for novel agents that inhibit the menin-MLL interaction for the treatment of various diseases and conditions, including leukemia, other cancers and diabetes.